Improvement in steam-boilers



UNITED STATES 'PATENT OFFICE.

JOHN DUNHAM, OF DETROIT, MICHIGAN.

IMPROVEMENT IN STEAM-BOlL-ERS.

Specification forming part of Letters Patent No, 31,704, dated March 19, 1861.

T0 aller/'homz't ntftg/ concern.;

Be it known that I, JOHN DUNHAM, of Detroit, in the county of Vayne and State of Michigan, have invented new and useful Improvements in Steam-Boilers;4 and I hereby declare that the following is a true and full description of the same, reference being had to the drawings herewith presented, which drawings constitute a part of said description.

My improvements consist in constructing the boiler so as to give a greater heating-surface without occupying any more room or requiring any more weight of metal than is used in boilers of the common construction. Air other advantage consists in consuming' all the smoke, thereby procuring more heat from a given quantity of fuel, and also getting rid of the nuisance of the smoke.

My boiler is constructed with a double series of tubes on each side of the furnace, (or ire-grate,) so arranged that the iiame passes from the rear end of the boiler through the lower series of tubes to the front end and then passes into the upper series of vtubes and through them to the rear end and then up the flue. (See the drawings.)

Figure l is an isometrical view of the exterior of the boiler. Fig. 2 is a horizontal section showing the arrangement of the tubes T T T. Fig. 3 is a section near the front at X, showing the grate-bars Gr and the watervessel NV, the tubes T, the air-register R, with its openings into the air-chamber in the windwall N. Fig. it is a longitudinal section having a portion of the inner plate removed, showing the interior arrangement and elevation of the parts. Fig. 5 is a section across the rear at Y, showing the tubes P P. Similar letters of reference indicate similar parts in each section. Fig. is a section of the wind-wall N. Fig. 7 is a transverse section of the salne, showing the air-chambers C C, the water-vessel W`, and the air-pipes P P. g

S shows the opening for steam to pass into the boiler, and it the passage for water from the boiler. This furnace or boiler being constructed with a special view to the economy of fuel and to saving of room, has also an apparatus for burning all the smoke.

It will be seen that a series of pipes, P P, are arranged to convey hot or cold air from the ai r-chamber O in the wind-wall N through the watervessel, delivering it in the flame at the top of the wind-wall. This vessel is kept full of water to prevent the pipes from burning away, and the quantity of air allowed to pass ctn be graduated at pleasure by the register R. (Seen at Fig. 3.) The water-vessel, being connected with the inside of the boiler, receives its water at the apertures u, and the steam that makes in it passes up into the boiler at S. It is important to have the steam pass out at the highest part of the vessel, for if the steam is allowed to accumulate it will not prevent the pipes from being burned away. This vessel might be made to open into the boiler by the whole bigness of its end, and it then becomes a part of the boiler. It may also be protected by clayv or brick.

It will be perceived that I get as much surface of tubes in a six-foot boiler by having' a double set of tubes as is obtained with a single series of tubes in a twelve-foot boiler of the common form, thereby saving half the room,4 also saving near half of the material of the boiler; and by putting a quantity of fresh air into the iiame I consume all the smoke and my air-pipes are protected from burning by the water-back. The air passing in below the fire-grate will be more or less heated and will consume the smoke more readily.

I do not claim the burning of the smoke by admitting fresh air, as that has been done before; neither do l claim the tubes when used in the way they have before been used.

What I claim as new, and desire to secure by Letters Patent, is-

Conducting the air in through the watervesseL'in combination with the several parts when constructed in the manner and for the purposes set forth.

In testimony whereof I subscribe in presence of two witnesses.

JOHN DUNHAM.

Vitiiesses:

JOHN WIGHTMAN, JOHN KATZENBHLER. 

